96results about How to "Reduce the noise floor" patented technology

A safety indicator monitors environment conditions detrimental to humans e.g., hazardous gases, air pollutants, low oxygen, radiation levels of EMF or RF and microwave, temperature, humidity and air pressure retaining a three month history to upload to a PC via infra red data interface or phone link. Contaminants are analyzed and compared to stored profiles to determine its classification and notify user of an adversity by stored voice messages from, via alarm tones and associated flashing LED, via vibrator for silent operation or via LCD. Environmental radiation sources are monitored and auto-scaled. Instantaneous radiation exposure level and exposure duration data are stored for later readout as a detector and dosimeter. Scans for EMF allow detection with auto scaling of radiation levels and exposure durations are stored for subsequent readout. Electronic bugs can be found with a high sensitivity EMF range setting. Ambient temperature measurements or humidity and barometric pressure can be made over time to predict weather changes. A PCS RF link provides wireless remote communications in a first responder military use by upload of alarm conditions, field measurements and with download of command instructions. The link supports reception of telemetry data for real time remote monitoring of personnel via the wrist band for blood pressure, temperature, pulse rate and blood oxygen levels are transmitted. Commercial uses include remote environmental data collection and employee assignment tasking. GPS locates personnel and reporting coordinates associated with alarm occurrences and associated environmental measurements.

A safety indicator monitors environment conditions detrimental to humans e.g., hazardous gases, air pollutants, low oxygen, radiation levels of EMF or RF and microwave, temperature, humidity and air pressure retaining a three month history to upload to a PC via infra red data interface or phone link. Contaminants are analyzed and compared to stored profiles to determine its classification and notify user of an adversity by stored voice messages from, via alarm tones and associated flashing LED, via vibrator for silent operation or via LCD. Environmental radiation sources are monitored and auto-scaled. Instantaneous radiation exposure level and exposure duration data are stored for later readout as a detector and dosimeter. Scans for EMF allow detection with auto scaling of radiation levels and exposure durations are stored for subsequent readout. Electronic bugs can be found with a high sensitivity EMF range setting. Ambient temperature measurements or humidity and barometric pressure can be made over time to predict weather changes. A PCS RF link provides wireless remote communications in a first responder military use by upload of alarm conditions, field measurements and with download of command instructions. The link supports reception of telemetry data for real time remote monitoring of personnel via the wrist band for blood pressure, temperature, pulse rate and blood oxygen levels are transmitted. Commercial uses include remote environmental data collection and employee assignment tasking. GPS locates personnel and reporting coordinates associated with alarm occurrences and associated environmental measurements.

A method and apparatus for locating integrated circuit defects associated with different aspects of the integrated circuit industry. The integrated circuit is configured in a known failing mode, with a first power supply providing a constant voltage and variable current. Next, one or more additional dedicated power supplies are connected to various points of interest throughout the integrated circuit, wherein these dedicated power supplies have a preset current and the voltage is allowed to vary. The integrated circuit is then scanned with a laser beam, which induces current changes on in the integrated circuit especially in defective areas. These current changes then cause voltage changes on the dedicated power supplies. When such a voltage change occurs on the dedicated power supplies, its position is noted.

An apparatus for generating bandwidth extension output data for an audio signal has a noise floor measurer, a signal energy characterizer and a processor. The audio signal has components in a first frequency band and components in a second frequency band, the bandwidth extension output data are adapted to control a synthesis of the components in the second frequency band. The noise floor measurer measures noise floor data of the second frequency band for a time portion of the audio signal. The signal energy characterizer derives energy distribution data, the energy distribution data characterizing an energy distribution in a spectrum of the time portion of the audio signal. The processor combines the noise floor data and the energy distribution data to obtain the bandwidth extension output data.

A pulsed radar system uses phase noise compensation to reduce phase noise due to drift of the reference oscillator to enable detection of micro movements and particularly human motion such as walking, breathing or heartbeat. The noise level due to A / D sampling must be sufficiently low for the phase noise compensation to be effective. As this is currently beyond state-of-the-art for high bandwidth A / D converters used in traditional receiver design, the receiver is suitably reconfigured to use analog range gates and narrowband A / D sampling having sufficiently low noise level. As technology continues to improve, the phase compensation techniques may be directly applicable to the high bandwidth A / D samples in traditional receiver designs. Whether phase compensation is applied to traditional receiver designs or a receiver configured with analog range gates, the steps are essentially the same: data is processed to position a reference range bin (either an analog range gate or a particular time sample) on a stationary reference and the phase variation of that reference range bin is used to compensate the phase of target data in range bins (either an ensemble of range gates or other time samples) near the stationary reference. This effectively moves the radar system and particularly the reference oscillator to the stationary reference thereby greatly reducing oscillator drift and phase noise and decoupling the stand-off range from the level of phase noise.

The invention relates to an integrated measurement system to detect a quantity of magnetic particles in a sample. The measurement system includes a substrate. An electromagnetic (EM) structure disposed on the surface of the substrate is configured to receive a sample including the magnetic particles in proximity thereof. The integrated measurement system also includes an electrical current generator disposed on the surface of the substrate which is electro-magnetically coupled to the EM structure. The electrical current generator is configured to cause an electrical current to flow in the EM structure. The integrated measurement system also includes an effective inductance sensor disposed on the surface of the substrate which is configured to measure a selected one of an effective inductance and a change in effective inductance. The invention also relates to a method to determine the number of and / or the locations of the magnetic particles in a sample.

A controller in a receiver monitors RSSI and AGC gain levels to determine signal conditions and adjust filter performance accordingly to optimize power consumption while providing acceptable signal quality. When RSSI level is high and AGC gain is low, a strong signal-of-interest is present. In this case, adaptive filter bias currents may be reduced raise the noise floor and degrade intermodulation to reduce power consumption because the strong signal-of-interest can tolerate the higher noise and distortion. When the RSSI level is low and AGC gain is high, a weak signal is present a low noise mode may be effected by increasing bias current to filters used to lower the noise floor, but intermodulation effects may still be tolerated so those filters may be cut back. Other cases are supported. RSSI and AGC gain level thresholds may be dynamically altered based on relative RSSI and AGC levels.

A method and system for reducing the overall noise floor in a wireless communication system, subsystem or network are disclosed, which reduces the output gain levels of specific uplink antenna transmitters during non-signal time periods (e.g., rest mode) when no communication signals are being conveyed between the mobile unit(s) and base station involved. The output gain level of each such uplink antenna's transmitter is decreased by a predetermined amount, which reduces the noise contribution of that uplink antenna, but also maintains the gain at a high enough level so that a signal can still pass from a mobile unit to the base station via that link, for example, during a call initiation attempt.

Synchronous circuitry for processing digital data in which the data are filtered to compensate for expected jitter in time-average frequency clock signals. Time-average frequency synthesis circuitry generates internal clock signals of a desired frequency, for example as based on a recovered clock signal from an input data stream, in a manner in which not all periods of the clock signal are of uniform duration. A jitter precorrection filter is inserted into the data path to apply a variable delay to pre-correct for distortion caused by jitter in the clock cycle. In embodiments of the invention using a flying-adder architecture to generate the clock signal, coefficients of the digital filer realizing the jitter precorrection filter are calculated according to the currently-selected oscillator phase and according to a fractional portion of a digital frequency control word.

A method and system for reducing the overall noise floor in a wireless communication system, subsystem or network are disclosed, which reduces the output gain levels of specific uplink antenna transmitters during non-signal time periods (e.g., rest mode) when no communication signals are being conveyed between the mobile unit(s) and base station involved. The output gain level of each such uplink antenna's transmitter is decreased by a predetermined amount, which reduces the noise contribution of that uplink antenna, but also maintains the gain at a high enough level so that a signal can still pass from a mobile unit to the base station via that link, for example, during a call initiation attempt.

The invention discloses a test method for current noise of a high-resistance device and a medium material, comprising the following test steps: firstly, arousing the low-frequency current noise of a high-resistance sample by utilizing a sample adapter; then amplifying the sample low-frequency noise by utilizing a low-noise current amplifier; collecting amplified noise signals by utilizing a data acquisition card; calculating the power spectrum density S0(f) of the collected current noise signals of which the high-frequency parts are attenuated by the amplifier; obtaining the amplitude-frequency characteristic curve of the current amplifier by utilizing a locking amplifier, and calculating a normalized curve Q(f) according to the amplitude-frequency characteristic curve; reducing the attenuated power spectrum density S0(f) by utilizing the Q(f), thus obtaining a power spectrum density curve S(f) of a reduced band spread; and finally, carrying out data analysis on the S(f) to screen devices or research sample reliability. By utilizing the test method, the problems of narrow times-number transmission band and insufficient test data in the existing test method for high-resistance sample noise are solved; and the test method provided by the invention has the advantages of high efficiency, automated operation and high precision of reduced data.

The invention relates to a portable all-purpose otoacoustic emission detecting system which belongs to the field of otoacoustic emission signal detectors and is characterized by comprising a portable PC (Personal Computer), a USB (Universal Serial Bus) sound card, a miniature loudspeaker, a miniature radio, a preprocessing circuit and a power supply, wherein the miniature loudspeaker comprises two sounders which can respectively send out stimulating sounds capable of evoking a transient evoked otoacoustic emission signal and a distortion product otoacoustic emission signal, the portable PC is provided with a USB sound card sensitivity calibration module and a miniature loudspeaker sensitivity calibration module, the PC, the USB sound card and the miniature loudspeaker form a stimulating sound playing path, and the miniature radio, the preprocessing circuit, the USB sound card and the PC form an otoacoustic emission signal acquisition path. The invention realizes the integrated detection for the transient otoacoustic emission signal and the distortion product otoacoustic emission signal and simultaneously realizes the portability of the all-purpose otoacoustic emission signal detecting system.

A sigma-delta modulator is provided. The sigma-delta modulator includes a differential amplifier which outputs a difference signal indicating a difference between an input analog signal and a feedback input analog signal, an integrator which integrates the difference signal, a band pass filter unit connected to the integrator in parallel which performs band pass filtering with respect to the difference signal, an adder which adds the band-pass filtered signal to the integrated signal, a comparator which compares a signal output from the adder with a predetermined reference value, converts the comparison result into a digital signal, and outputs the digital signal; and a digital-to-analog (D / A) which converts the digital signal output from the comparator into an analog signal and feeds the analog signal back to the differential amplifier.

An amplifier may include two or more pulse-width modulators controlling respective sets of switches to produce an amplified version of a source signal. A positive DC-offset based on the source signal may be applied to the pulse-width modulator controlling one respective set of switches, and an equal value negative DC-offset may be applied to the pulse-width modulator controlling the other respective set of switches, to provide an effective offset between the respective points in time of the rising / falling edges of the different pulse-width modulated control signals. The addition of alternating positive and negative DC-offset values doesn't affect the output load, and doesn't degrade the signal. The DC-offsets may be added at a frequency selected to be beyond the signal baseband, and the value of the small input signal level may be determined using an RMS level comparator or similar measurement technique.

A method for processing a frequency division multiplexing signal transmitted in a channel is provided. The method includes the steps of a) receiving the frequency division multiplexing signal having a residual intercarrier interference (ICI) and a channel noise and transmitted by plural subcarriers; b) performing a cyclic prefix removal and a discrete Fourier transform for the frequency division multiplexing signal to obtain a frequency-domain signal; c) analyzing the frequency-domain signal to obtain a plurality of correlation values for the residual ICI and the channel noise; and d) performing a communication signal processing for the frequency division multiplexing signal based on at least one of the plural correlation values.

An integrated fiber interferometry interrogator for generating superimposed waves is disclosed. The system is optimized for efficiency and vibration attenuation. The system comprises an optical light source for generating a first signal, a first signal splitter which splits the first signal into a reference signal and an interrogation signal, optical modulators for modulating the signals, a fiber coupler connected to a fiber under test, an isolator, a circulator with a plurality of connections for directing the signals, a signal mixer for mixing the signals into superimposed waves, and photo diodes for receiving the superimposed waves.

The invention discloses a weak grating array distributed vibration sensing system and a weak grating array distributed vibration sensing method, belongs to the technical field of fiber grating sensing, and solves the problems that demodulation by using a double-arm interferometer in the prior art is easily interfered by an external environment, the bottom noise is large, and the frequency responsebandwidth is relatively narrow. The weak grating array distributed vibration sensing system comprises: a narrow linewidth laser used for generating continuous light with a certain central wavelength;an acoustic optical modulator that is used for modulating the continuous light into a corresponding double-pulse signal; a circulator that is used for transmitting the double-pulse signal to the weakgrating array. The weak grating array reflects the double-pulse signal to a circulator; the circulator is also used for transmitting the reflected double-pulse signal to the 3 * 3 coupler; the 3 * 3coupler is used for enabling the reflected double-pulse signal to form interference and generating an interference signal; and the system also includes a photoelectric detector that is used for acquiring interference signals and converting the interference signals into electric signals. According to the invention, the system bottom noise is reduced, and the signal-to-noise ratio and the frequencyresponse range are improved.

A pulsed radar system uses phase noise compensation to reduce phase noise due to drift of the reference oscillator to enable detection of micro movements and particularly human motion such as walking, breathing or heartbeat. The noise level due to A / D sampling must be sufficiently low for the phase noise compensation to be effective. As this is currently beyond state-of-the-art for high bandwidth A / D converters used in traditional receiver design, the receiver is suitably reconfigured to use analog range gates and narrowband A / D sampling having sufficiently low noise level. As technology continues to improve, the phase compensation techniques may be directly applicable to the high bandwidth A / D samples in traditional receiver designs. Whether phase compensation is applied to traditional receiver designs or a receiver configured with analog range gates, the steps are essentially the same: data is processed to position a reference range bin (either an analog range gate or a particular time sample) on a stationary reference and the phase variation of that reference range bin is used to compensate the phase of target data in range bins (either an ensemble of range gates or other time samples) near the stationary reference. This effectively moves the radar system and particularly the reference oscillator to the stationary reference thereby greatly reducing oscillator drift and phase noise and decoupling the stand-off range from the level of phase noise.

A high power laser with chirped pulse amplification to produce extremely high power ultrashort pulses is disclosed. A pulse stretcher and methods of stretching a laser pulse are also disclosed. The pulse stretcher comprises: a first diffraction grating (G1) arranged to receive and disperse a seed laser pulse; transfer optics (CM) arranged to collect the dispersed pulse and direct it to a transmission diffraction grating (G2) which is either the first diffraction grating or a second diffraction grating; the transmission diffraction grating arranged to collimate the collected pulse to a reflector (BM), the reflector arranged such that the pulse is reflected back through the pulse stretcher via the transmission diffraction grating. The pulse stretcher provides better phase noise performance of the output pulse, and therefore a reduction in the noise floor to improve contrast pedestal.

The present disclosure is a infrared sensor capable of being integrated into a IR focal plane array. It includes of a CMOS based readout circuit with preamplification, noise filtering, and row / column address control. Using either a microbolometer device structure with either a thermal sensing element of vanadium oxide or amorphous silicon, a nanocomposite is fabricated on top of either of these materials comprising aligned or unaligned carbon nanotube films with IR trans missive layer of silicon nitride followed by one to five monolayers of graphene. These layers are connected in series minimizing the noise sources and enhancing the NEDT of each film. The resulting IR sensor is capable of NEDT of less than 1 mK. The wavelength response is from 2 to 12 microns. The approach is low cost using a process that takes advantage of the economies of scale of wafer level CMOS.

A single-point modulator (1) has a PLL circuit (2) and a programmable frequency divider (7) whose control connection is connected to a circuit branch for injecting a digital modulation signal (15) which is arranged in the feedback path of the PLL circuit (2). The circuit branch contains a sigma-delta modulator (9) which, in turn, has a digital filter (24) having a transfer function H(z). The noise transfer function NTF(z) of the sigma-delta modulator (9) is given by the function NTF(z)=1−H(z).

An exemplary magnetic flux sensor in accordance with the present invention is characterized by an electrical output that is proportional to the total static and dynamic flux passing normally through a large area. An oscillating electrical current passing down a conducting area produces Lorentz forces, which are transferred to piezoelectric areas. The piezoelectric areas produce electrical voltage at the oscillation frequency whereby amplitude is proportional to the total magnetic flux passing normally through the conducting area. Demodulating the voltage provides an electrical signal with high sensitivity, dynamic range, and noise immunity.

A system for processing a signal includes a detector configured to detect a two-level stream of bits; a converter configured to generate a three-level control signal based on two adjacent values within the two-level stream of bits; and a switch configured to determine which of three different paths to couple a current source to based on a value of the three-level control signal. Thus, based on adjacent values of the output stream a three-level control signal is generated which controls coupling of the current source to one of three different paths. This type of three-level digital-to-analog converter can be, for example, part of the feedback loop of an analog-to-digital converter. Similar techniques can also be utilized in a multi-segment digital-to-analog converter in which each segment of the DAC is controlled by a 3-level control signal and the DAC is implement using PMOS devices. The current source for each DAC segment is diverted to ground, the M-node, or the P-node depending on the value of the 3-level control signal.

The invention provides a dynamic in-situ gas-phase reaction tank for a soft X-ray spectroscopy experiment. The dynamic in-situ gas-phase reaction tank comprises a reaction tank main body, a reaction tank supporting piece and an external connecting piece. The reaction tank main body is provided with a sample cavity for placing a sample and a first light through hole communicated with the sample cavity, and a metal partition plate is arranged in the sample cavity. The reaction tank supporting piece comprises a supporting pipe, and the supporting pipe is connected with the reaction tank main body. The external connecting piece comprises a connector, a differential pumping pipeline, an electronic yield signal line and a bias line, and one end of the bias line sequentially penetrates through the differential pumping pipeline, the connector, the supporting pipe and the reaction tank main body to be connected with the metal partition plate. According to the invention, a bias voltage is applied to the metal partition plate, so that an electric field is generated between the sample and the metal partition plate, ionized gas particles are pulled away from the surface of the sample, background noise is reduced, and collection of electron yield signals becomes possible; and the reasonable Reynolds coefficient is achieved by reducing the distance between the window and the sample and adjusting the gas flow rate, and therefore it is guaranteed that the gas updating speed on the surface of the material is high.

A spectrally efficient multi-carrier communication apparatus with advanced features of carrier management. The apparatus is flexible to changes in the form of the sub-carrier and their location in frequency. This invention can use non-standard pulses at arbitrary frequencies providing a greater control of the carrier. The additional features can be used for spectral efficiency, to correct signal distortion or for privacy. Also disclosed is a novel multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM), preferred embodiments of the transmitter and receiver. Two complementary algorithms help the invention excel among other existent methods. The disclosed algorithms can similarly be adapted to other systems. A correction method for spectrally efficiency is calibrated to all desired noise levels for maximum benefit. An iterative multi-carrier reduction method dramatically reduces the error on overlapped subcarriers.

Synchronous circuitry for processing digital data in which the data are filtered to compensate for expected jitter in time-average frequency clock signals. Time-average frequency synthesis circuitry generates internal clock signals of a desired frequency, for example as based on a recovered clock signal from an input data stream, in a manner in which not all periods of the clock signal are of uniform duration. A jitter precorrection filter is inserted into the data path to apply a variable delay to pre-correct for distortion caused by jitter in the clock cycle. In embodiments of the invention using a flying-adder architecture to generate the clock signal, coefficients of the digital filer realizing the jitter precorrection filter are calculated according to the currently-selected oscillator phase and according to a fractional portion of a digital frequency control word.

The invention relates to a transmission device for transmitting ions in a proton transfer reaction ion source. The transmission device comprises an annular transmission focusing electrode, an introducing electrode and an extracting electrode which are coaxially arranged, wherein the annular transmission focusing electrode is positioned between the introducing electrode and the extracting electrode, an ion introducing port is formed in the center of the introducing electrode, and an ion extracting port is formed in the center of the introducing electrode; the center of the annular transmission focusing electrode is provided with a funnel-shaped ion focusing transmission passage, the tail end of the ion focusing transmission passage faces the ion extracting port, the ion introducing port, the ion transmission passage and the ion extracting port are communicated, and the ion transmission passage is internally provided with a jet flow blocking electrode. According to the transmission device, the ion utilization efficiency of the proton transfer reaction mass spectrum ion source can be improved, the problem that the transmission efficiency of an existing ion transmission method is insufficient is solved, and finally the sensitivity of a proton transfer reaction mass spectrometer is improved.

A capacitive microphone and method of fabricating the same are provided. One or more holes can be formed in a first printed circuit board (PCB). A diaphragm can be surface micro-machined onto an interior surface of the first PCB at a region having the one or more holes. Interface electronics can also be interconnected to the interior surface of the PCB. One or more spacer PCBs can be attached to a second PCB to the first PCB, such that appropriate interconnections between interconnect vias are made. The second PCB and first PCB with spacers in between can be attached so as to create a cavity in which the diaphragm and interface electronics are located.

A frequency detection method based on resonator synchronization oscillations and an inclination angle sensor thereof are provided; detection elements and a synchronization element are respectively placed in a first and second oscillation circuits so as to form two self excited oscillators; the detection elements and the synchronization element are coupled through a plate capacitor, so weak synchronization current can pass through, thus affecting and reducing the detection element oscillator phase noises, and greatly improving the frequency stability; the fixed frequency can be read through a frequency counter; the three detection elements are evenly distributed around a hexagon mass block respectively through an amplification beam; the mass block is used for sensing the gravitational acceleration and applying tension force on the amplification beams; the amplification beams amplify and transfer the force to the detection elements, thus changing the self-excited oscillation frequency, and forming synchronization self-excited oscillation; the oscillation frequencies and changes of three synchronization self-maintained circuits can be detected, thus inversing the acceleration size and direction received by the whole device.

The invention relates to a heat dissipation structure of a large-target-surface image sensor. The heat dissipation structure comprises an image sensor board, a heat dissipation panel and a casing front cover; the image sensor board comprises an image sensor circuit board, an image sensor base and an image sensor chip; the image sensor base is fixed on the image sensor circuit board; the heat dissipation panel is mounted on the image sensor base, the heat dissipation panel is provided with rectangular through holes, pins of the image sensor chip are inserted into the rectangular through holes and is connected with the image sensor base; and the image sensor board presses and mounts the heat dissipation panel on the casing front cover. The heat dissipation structure provided by the inventiondissipates heat by virtue of the heat dissipation panel and also dissipates the heat by virtue of a PCB mounted on the casing front cover, structure is simple and compact, the problem of compact layout is dramatically solved, the aim of heat dissipation of the large-target-surface image sensor can be realized, and disassembly and assembly of the image sensor also can be facilitated.